bug#19840: "Bad uri header component" when downloading from gitorious.org

[Ricardo Wurmus]

Downloading archives from gitorious fails:

    ~/dev/guix $ ./pre-inst-env guix download 
https://gitorious.org/lv2-synths/lv2-mdametapiano/archive/0.0.1.tar.gz
    starting download of `/tmp/guix-file.gqYdZs' from 
`https://gitorious.org/lv2-synths/lv2-mdametapiano/archive/0.0.1.tar.gz'...
    ERROR: Bad uri header component: 
/lv2-synths/lv2-mdametapiano/archive/ceb5345396425ad526be34c79eae2b4dfe886d5b.tar.gz
    
    failed to download "/tmp/guix-file.gqYdZs" from 
"https://gitorious.org/lv2-synths/lv2-mdametapiano/archive/0.0.1.tar.gz";
    guix download: error: 
https://gitorious.org/lv2-synths/lv2-mdametapiano/archive/0.0.1.tar.gz: 
download failed

Here the same with wget -S:

    ~/dev/guix $ wget -S 
https://gitorious.org/lv2-synths/lv2-mdametapiano/archive/0.0.1.tar.gz
    --2015-02-11 20:48:30--  
https://gitorious.org/lv2-synths/lv2-mdametapiano/archive/0.0.1.tar.gz
    Resolving gitorious.org (gitorious.org)... 87.238.52.168, 2a02:c0:1014::1
    Connecting to gitorious.org (gitorious.org)|87.238.52.168|:443... connected.
    HTTP request sent, awaiting response... 
      HTTP/1.1 302 Found
      Server: nginx
      Date: Wed, 11 Feb 2015 19:48:30 GMT
      Content-Type: text/html;charset=utf-8
      Content-Length: 211
      Connection: keep-alive
      Status: 302 Found
      Location: 
/lv2-synths/lv2-mdametapiano/archive/ceb5345396425ad526be34c79eae2b4dfe886d5b.tar.gz
      X-XSS-Protection: 1; mode=block
      X-Content-Type-Options: nosniff
      X-Frame-Options: SAMEORIGIN
      X-UA-Compatible: IE=Edge,chrome=1
      Cache-Control: no-cache
      Set-Cookie: 
_gitorious_session=BAh7BkkiD3Nlc3Npb25faWQGOgZFVEkiJTJhOTEzZTJmZTVjZjZhZDRkMDU2NTA1ZWQ1NDhhZDY1BjsAVA%3D%3D--dde27a4488e6aef56d25db1dbf58ee75f36fd1bf;
 domain=.gitorious.org; path=/; expires=Wed, 04-Mar-2015 19:48:30 GMT; secure; 
HttpOnly
      X-Request-Id: 55889cfebab9c8dc6e1745825510ae13
      X-Runtime: 0.015907
      Strict-Transport-Security: max-age=31536000
    Location: 
/lv2-synths/lv2-mdametapiano/archive/ceb5345396425ad526be34c79eae2b4dfe886d5b.tar.gz
 [following]
    --2015-02-11 20:48:30--  
https://gitorious.org/lv2-synths/lv2-mdametapiano/archive/ceb5345396425ad526be34c79eae2b4dfe886d5b.tar.gz
    Reusing existing connection to gitorious.org:443.
    HTTP request sent, awaiting response... 
      HTTP/1.1 200 OK
      Server: nginx
      Date: Wed, 11 Feb 2015 19:48:30 GMT
      Content-Type: application/x-gzip; charset=utf-8
      Content-Length: 1938720
      Connection: keep-alive
      Cache-Control: no-cache
      Set-Cookie: 
_gitorious_session=BAh7BkkiD3Nlc3Npb25faWQGOgZFVEkiJTJhOTEzZTJmZTVjZjZhZDRkMDU2NTA1ZWQ1NDhhZDY1BjsAVA%3D%3D--dde27a4488e6aef56d25db1dbf58ee75f36fd1bf;
 domain=.gitorious.org; path=/; expires=Wed, 04-Mar-2015 19:48:30 GMT; secure; 
HttpOnly
      Accept-Ranges: bytes
      Content-Disposition: attachment; 
filename=lv2-synths-lv2-mdametapiano-ceb5345396425ad526be34c79eae2b4dfe886d5b.tar.gz
      Last-Modified: Wed, 11 Feb 2015 19:34:43 GMT
      Strict-Transport-Security: max-age=31536000
    Length: 1938720 (1.8M) [application/x-gzip]
    Saving to: ‘0.0.1.tar.gz’
    
    0.0.1.tar.gz        100%[=====================>]   1.85M  1.36MB/s   in 
1.4s   
    
    2015-02-11 20:48:32 (1.36 MB/s) - ‘0.0.1.tar.gz’ saved [1938720/1938720]